Duo Halloween Costume: Zack and Slater From "Saved by the Bell" Head to the thrift store and scope out '90s-inspired pieces to bring this duo costume idea to life. You'll probably have the catchy "Saved by the Bell" theme song stuck in your head all night long. What to wear for Zack: Two words: frosted tips. Once you've got those, throw in a pair of high-tops and a flashy t-shirt. What to wear for Slater: Acid-wash jeans and a muscle tank that shows off your arms. Image Source: Everett Collection